| objective:To explore the value of dynamic contrast enhanced magnetic resonance imaging(DCE-MRI)quantitative parameters Ktrans,Kep,Ve and ADC in evaluating the degree of differentiation,T staging and lymph node metastasis of rectal cancer.Methods:search 89 cases of rectal cancer patients in Sichuan Provincial People's Hospital from February 2017 to November 2017,All patients received routine MRI,DWI and DCE-MRI scan before operation,According to the inclusion criteria,53 patients who were required to meet the requirements were considered as the subject of the study.The results of surgical pathology were used as the "gold standard".According to the degree of differentiation,53 cases of patients were divided into 3 groups: high differentiation group of 13 cases,30 cases in middle differentiation group and 10 cases in low differentiation group.According to the 2016 eighth edition of UICC/AJCC staging system,53 cases of patients were divided into 4 groups: T1 group of5 cases,T2 group of 8 cases,T3 group of 24 cases,T4 group of 16 cases;According to the metastasis of lymph node,53 patients were divided into 2 groups: lymph node metastasis group of 7 cases and non lymph node metastasis group of 36 cases.A review group consists of two senior doctors and 1 resident physicians,analysis of DCE-MRI and DWI images of all patients,Processing images by post processing software and measuring Ktrans,Kep,Ve,and ADC values.The difference of parameter values of different differentiationdegree,pathological stage and lymph node metastasis with single factor variance analysis,SNK-q test was used to compare the differences between the two groups which has statistically significant factor,The test level is alpha =0.05;Drawing ROC curves for the parameter values of two adjacent groups with statistically significant differences,count The area under the curve and sensitivity and specificity of each parameter,selcet the biggest sum of sensitivity specificity as a threshold to distinguish two groups.Results:(1)The difference in Ktrans value of rectal cancer patients with different degree of differentiation was statistically significant(p=0.004),The difference of Kep value was not statistically significant(p=0.452),the difference of Ve value was not statistically significant(p=0.331),and the difference of ADC value was statistically significant(p=0.000).Analysis the Ktrans values of the differentiationdegree between two adjacent groups,The difference of Ktrans value between the high and middle differentiation groups was statistically significant(p=0.016),and the difference of Ktrans values between the middle and low differentiation groups was statistically significant(p=0.011).USE the Ktrans value of the high and middle differentiationrectal cancerpatients to plot ROC curve,the area under the curve was 0.677 and the threshold was 0.1795(sensitivity =0.767,specificity =0.538).USE the Ktrans value of themiddle and low differentiatedrectal cancerpatients to plot ROC curve,The area under the curve was 0.693 and the threshold was 0.2805(sensitivity =0.500,specificity =0.900).Analysis the ADC values of the differentiation degree between two adjacent groups,the difference of ADC between the high and middle differentiation groups was statistically significant(p=0.012),and the ADC value between the moderately and poorly differentiated groups was statistically significant(p=0.000).USE the ADC value of the high and middle differentiationrectal cancerpatients to plot ROC curve,The area under the curve is 0.763,the threshold is 1.1790(sensitivity =0.769,specificity =0.733).USE the ADC value of the patients with middle and low differentiationrectal cancerpatients to plot ROC curve,The area under the curve is 0.967,and the threshold is 0.9055(sensitivity =0.967,specificity =1.00).(2)There was a significant difference in Ktrans value between rectal cancer patients with different T stages(p=0.002),kep value was not statistically significant(p=0.062),Ve value was not statistically significant(p=0.148),ADC value difference was statistically significant(p=0.007).Analysis the Ktrans value of T staging in two adjacent groups,there was not significant difference in Ktrans value between group T1 and T2(p=0.781),there was a statistically significant difference in Ktrans between T2 and T3 groups(p=0.009),and there was not significant difference in Ktrans value between T3 and T4 groups(p=0.932).USE the Ktrans value of rectal cancer patients with T2 and T3 staging to plot ROC curve,the area under the curve was 0.862,and the threshold was 0.2035(sensitivity =0.792,specificity =0.875).Analysis the ADC value of T stage in two adjacent groups,there was a significant difference in ADC value between T2 and T3 group(p=0.013),there was not significant difference between the T1 and T2 group,and there was aslo not significant difference between the T3 and T4 group(p=0.535,p=0.524).USE the ADC value of the rectal cancerpatients with T2 and T3 stage to plot ROC curve,the area under the curve was 0.742,and the threshold was 1.5785(sensitivity =0.500,specificity =0.958).There was a significant difference in ktrans value between lymph node metastasis or non lymph node metastasis(p=0.000),and there was not significant difference in Kep value(p=0.253),Ve value was not statistically significant(p=0.172),ADC value difference was not statistically significant(p=0.086).USE the Ktrans value to plot ROC curve,the area under the curve was 0.836,and the threshold was 0.2085(sensitivity =0.882,specificity =0.722).Conclusions:(1)Along with the decrease of the differentiation degree of rectal cancer,the Ktrans value increased(P < 0.05).Along with the decrease of the differentiation degree of rectal cancer,the ADC value decreased(P < 0.05).Ktrans and ADC can be used as reference indicators for differentiating highly differentiated and middle differentiated rectal cancer.But the diagnostic efficiency of Ktrans was lower than that of ADC(the area under ROC curve was 0.677 and 0.763 respectively),and the sensitivity and specificity of ADC threshold identification for high and middle differentiated rectal cancer are higher than that of Ktrans threshold.Ktrans and ADC can also be used as reference index for differentiating middle differentiated and low differentiated rectal cancer,the diagnostic efficiency of Ktrans was also lower than that of ADC(the area under the ROC curve was 0.693 and 0.693,respectively),and the sensitivity and specificity of Ktrans threshold identification for low and middle differentiated rectal cancer are lower than that of ADC threshold.(2)The Ktrans value of rectal cancer at different T stages was statistically significant(P < 0.01),and the ADC value of rectal cancer at different T stages was statistically significant(P < 0.05).Ktrans and ADC can be used as reference indicators for the identification of T2 and T3 stage rectal cancer.The diagnostic efficiency of Ktrans was higher than that of ADC(the area under the ROC curve was 0.862 and 0.742,respectively),the sensitivity of Ktrans threshold to T2 and T3 stage rectal cancer was higher than that of ADC,but its specificity was lower than that of ADC.(3)Ktrans can be used as a reference indicator for differentiating lymph node metastasis or not of rectal cancer(P < 0.05),the diagnostic efficiency and the sensitivity and specificity of threshold are superior.In conclusion,some quantitative parameters of MRI,especially Ktrans and ADC,can be used as an important reference indicators for preoperative assessment of rectal cancer's differentiation degree,T stage and lymph node metastasis accurately,it's of profound significance to the treatment and prognosis of the patients. |
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